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DD Series — High-Capacity Inverter Ducted Dehumidifiers, 140–960 L/day.

Q: How do I calculate the moisture load for a commercial or industrial space?

Moisture-load calculation (latent load) follows the same framework as cooling-load calculation. Total latent load sums internal sources (people 40–70 g/h each, process moisture, infiltration), boundary sources (vapour migration, drying building materials), and operational sources (cleaning, condensation, occupancy peaks). ASHRAE provides moisture-emission rates by occupancy and process type. Indoor pool halls follow ASHRAE TC 9.6 or SwimAir methods, factoring water surface, temperature differential, and activity. For project sizing, contact DanVex via the dealer network.

Q: What is Full Inverter technology, and why does it matter for industrial dehumidification?

Full Inverter — an inverter system: inverter compressor and inverter-driven fan. The compressor varies rotational speed continuously to match real moisture load, instead of running at fixed speed and cycling on/off. Three consequences: (1) Stable humidity — fixed-speed units swing ±10–15% RH, inverter units hold ±2–3% RH; matters for museums, pharma, plant cultivation. (2) Energy efficiency — typical savings 20–40% over a year at part-load operation. (3) Compressor longevity — fewer start-stop cycles mean less mechanical stress. Across the DD Series, Full Inverter is complemented by an electronic expansion valve (EEV), regulating airflow and refrigerant flow continuously to hold capacity and efficiency steady under changing load.

Q: What is E-Coating, and why does DanVex use it across the range?

E-Coating (electrochemical deposition coating) is an anti-corrosion treatment for the aluminium fins of a refrigerant heat exchanger, applied by immersion in an electrically charged bath so the polymer layer deposits uniformly over the entire fin surface — including internal and shaded areas — for full 360° protection. It resists moisture, mild acids and alkalis, salt vapours, and chlorinated air, suiting the full span of environments the DD Series serves: warehouses, food production, manufacturing, museums, plant cultivation, and indoor pool halls. DanVex fits E-Coating on every model in the DD Series; the right model is selected by moisture load, airflow, and static pressure, not by coating type.

Q: What static pressure does my ducting network require?

External static pressure (ESP) is the resistance the fan overcomes in the duct network — duct friction, fittings, filter pressure drop, diffusers, silencers. Typical values: short residential loops 80–150 Pa; standard commercial 150–250 Pa; extended industrial 250–400 Pa. Calculate total drop and add 20% safety margin for filter loading. The DD Series provides two tiers: 200 Pa on DD-168 / 240 / 380 / 480; 400 Pa on DD-720 / 960. Select with 20% headroom above the calculated value.

Q: What humidity level should I maintain in common industrial applications?

Industry targets by application: indoor pool halls 50–60% at +28 to +30 °C water; food production 45–65% by product (lower for cured goods, higher for proofing); plant cultivation 60–70% vegetative, 40–55% flowering; warehouses 50–65% general, 30–45% electronics; museums and archives 45–55% with ±5% stability (ISO 11799); pharmaceutical 30–50% per GMP; manufacturing 40–60% general. Sizing depends on moisture load — process emission rate, infiltration, occupancy — not floor area alone.

Q: What is Hot Gas Defrost, and how is it different from natural defrost?

When a dehumidifier operates near +5 to +10 °C, condensate freezes on the evaporator coil and the unit runs a defrost cycle. Natural defrost switches the compressor off and uses room air to melt ice — 20–30 minutes with no useful dehumidification. Hot Gas Defrost routes the compressor's hot discharge gas directly to the evaporator coil through a bypass valve; ice melts in approximately 3 minutes. 10× shorter interruption — critical for continuous-duty industrial applications. Hot Gas Defrost is standard on all DanVex DD, DD-F, and DD-FX models.

Q: Can a dehumidifier replace humidity control on an HVAC AHU, or do they work together?

Both approaches are used. Integrated AHU humidity control (reheat coil or refrigerant-DX stage in the air handler) works in new-build projects where the AHU is sized for humidity duty from the start. Dedicated dehumidifier in series or parallel with the AHU — like the DanVex DD Series — is typical for retrofits where the existing AHU cannot deliver target RH, or where humidity duty is a localised requirement. Standalone dehumidifiers have lower capital cost than AHU modification, faster project timeline, and easier maintenance.

DD Series · High-Capacity Ducted

DD Series — High-Capacity Inverter Ducted Dehumidifiers, 140–960 L/day

High-capacity ducted models from 140 to 960 L/day for commercial and industrial applications: indoor pools, warehouses, food production, plant cultivation, manufacturing, and public facilities. Three-phase 380–415 V, R-32 refrigerant, Full Inverter technology (inverter compressor and inverter-driven fan) with precise airflow regulation, electronic expansion valve (EEV) for maximum refrigerant-circuit efficiency, E-Coating heat-exchanger protection, 5-in-1 air sensor, Modbus RTU RS-485 + Wi-Fi. Concealed Ultra-Slim installation; single intake / single supply, operates standalone or integrates with central ventilation.

Capacity140–960L/day

Airflow1700–11 000m³/h

Static pressure200–400Pa

Supply3-Phase 380–415 V

RefrigerantR-32

Air sensor5-in-1

About the DD Series

The DanVex DD Series is a range of high-capacity ducted dehumidifiers designed for permanent installation in commercial and industrial spaces where moisture control is a continuous operational requirement: indoor pool halls and spas, food and beverage production, warehouses and logistics centres, plant cultivation facilities, manufacturing halls, museums and archives, and other large-volume environments.

Capacity ranges from 140 L/day (DD-168) to 960 L/day (DD-960), with supply airflow from 1700 m³/h to 11 000 m³/h and external static pressure from 200 Pa to 400 Pa — sufficient for both standalone duct loops and integration with central ventilation networks. All models run on three-phase 380–415 V supply and use R-32 refrigerant. Each unit is built into an Ultra-Slim concealed housing for installation within ceiling cavities or technical spaces; the durable powder-coated steel cabinet also permits outdoor installation where required.

Every model in the DD Series is built on Full Inverter technology: inverter compressor and inverter-driven fan with precise airflow regulation. The compressor varies output continuously to match the real moisture load — eliminating humidity swings and reducing power consumption — while the inverter-driven fan holds airflow steady against changing duct resistance. An electronic expansion valve (EEV) meters refrigerant flow precisely across the full operating range, keeping the refrigeration circuit at peak efficiency and capacity under varying load and ambient conditions. Heat-exchanger protection is E-Coating across the range: an electrochemical anti-corrosion layer that deposits uniformly over the entire fin surface, resisting moisture, mild acids and alkalis, salt vapours, and chlorinated air — suitable for the full span of commercial and industrial environments the series serves, from warehouses to pool halls and food production.

Models in the Range

DD-168 140–210 L/day · 1700–2200 m³/h · 200 Pa · 108 kg · Full Inverter, E-Coating

Indicative coverage: ~150–300 m² depending on conditions

For medium-sized commercial spaces with moderate moisture loads: small indoor pools, mid-size warehouses, food retail back-rooms, mid-volume plant cultivation rooms, public facility basements. Variable output 1830–2520 W, R-32 × 1600 g.

DD-240 220–260 L/day · 1900–2700 m³/h · 200 Pa · 119 kg · Full Inverter, E-Coating

Indicative coverage: ~200–400 m² depending on conditions

For larger commercial spaces: hotel pool areas, mid-size warehouses, larger food retail and storage, museum archives, larger plant cultivation rooms. Variable output 3040–4200 W, R-32 × 1800 g.

DD-380 300–420 L/day · 3500–3850 m³/h · 200 Pa · 189 kg · Full Inverter, E-Coating

Indicative coverage: ~350–600 m² depending on conditions

For large commercial and light industrial: commercial pool halls, food and beverage production rooms, large warehouses, manufacturing areas with controlled humidity zones, professional cultivation facilities. Variable output 4580–6246 W, R-32 × 2500 g.

DD-480 480 L/day · 4800–5300 m³/h · 200 Pa · 200 kg · Full Inverter, E-Coating

Indicative coverage: ~450–750 m² depending on conditions

For demanding commercial and industrial environments with high moisture and chemical loads: large pool halls, food processing with active wet cycles, large-scale cultivation facilities, industrial manufacturing rooms. E-Coating heat exchanger for aggressive atmospheres. Output 9000 W, R-32 × 2800 g.

DD-720 720 L/day · 7500–9000 m³/h · 400 Pa · 422 kg · Full Inverter, E-Coating

Indicative coverage: ~700–1100 m² depending on conditions

For large industrial facilities and multi-zone installations: Olympic-scale pool halls, large food production lines, large-volume warehouses, multi-room cultivation complexes, central HVAC integration with long duct runs. Full Inverter technology with EEV control delivers stable high-capacity dehumidification under varying load. 15 000 W, R-32 × 5400 g.

DD-960 960 L/day · 9000–11 000 m³/h · 400 Pa · 450 kg · Full Inverter, E-Coating

Indicative coverage: ~1000–1500 m² depending on conditions

For very large industrial facilities and central HVAC integration: very large pool complexes, large-scale food production halls, distribution warehouses, multi-zone industrial sites, central building moisture management. Full Inverter technology with EEV control for stable output at maximum capacity. 21 000 W, R-32 × 7200 g.

Coverage figures are indicative for typical commercial and industrial conditions (medium moisture load, ceilings around 3–6 m, normal air-change rates). Actual sizing depends on initial RH, target RH, ceiling height, infiltration, process moisture sources, and whether the unit operates standalone or integrates with central ventilation. For pool halls, food production with active wet cycles, plant cultivation with active transpiration, or very large open spans, contact us for project-specific sizing — high-capacity selection benefits from a moisture-load calculation rather than rule-of-thumb area coverage.

Which Model Should I Choose?

The DD Series covers the capacity range from 140 to 960 L/day. Use this table to narrow the choice by capacity, static pressure, and airflow — full parameters are in the specifications table below.

Selection criteria	DD-168	DD-240	DD-380	DD-480	DD-720	DD-960
Capacity	140–210 L/day	220–260 L/day	300–420 L/day	480 L/day	720 L/day	960 L/day
Supply airflow	1700–2200 m³/h	1900–2700 m³/h	3500–3850 m³/h	4800–5300 m³/h	7500–9000 m³/h	9000–11 000 m³/h
Static pressure	200 Pa	200 Pa	200 Pa	200 Pa	400 Pa	400 Pa
Inverter system	Full Inverter	Full Inverter	Full Inverter	Full Inverter	Full Inverter	Full Inverter
Heat exchanger	E-Coating	E-Coating	E-Coating	E-Coating	E-Coating	E-Coating
Indicative coverage	~150–300 m²	~200–400 m²	~350–600 m²	~450–750 m²	~700–1100 m²	~1000–1500 m²
Best for	Mid-size commercial, moderate loads	Larger commercial, hotel pools	Large commercial / light industrial	Aggressive atmospheres — pools, food, cultivation	Large industrial, multi-zone, long duct runs	Very large industrial, central HVAC

Where Is the DD Series Used?

The DD Series targets continuous high-capacity humidity control in commercial and industrial settings — permanent installations where moisture removal is part of the operational specification, not an occasional intervention. Typical environments:

Indoor Pools & Spas

Warehouses & Logistics

Food Production

Manufacturing

Plant Cultivation

Museums & Archives

Application Guide

Application	Target RH	Typical loads	Recommended DD models
Indoor pools, spas, water-parks	50–60%	High latent load from open water; chlorine atmosphere	DD-380, DD-480, DD-720, DD-960
Food production halls	45–60%	Process moisture; cleaning cycles; aggressive cleaning agents	DD-380, DD-480, DD-720
Warehouses & distribution	50–65%	Air-leakage moisture; loading-bay infiltration; condensation prevention	DD-240, DD-380, DD-720, DD-960
Plant cultivation (indoor agriculture)	50–65% (vegetative) / 40–55% (flowering)	Continuous transpiration; tight RH targets; cyclical loads	DD-240, DD-380, DD-480, DD-720
Manufacturing (general)	40–60%	Process moisture; corrosion prevention on stored materials	DD-168, DD-240, DD-380, DD-480
Museums, archives, libraries	45–55% (stable)	Low load but tight RH stability; valuable contents	DD-168, DD-240, DD-380 (Full Inverter for stability)
Pharmaceutical and clean production	30–50%	Strict RH control; HEPA-compatible duct system	DD-168, DD-240, DD-380 (with downstream HEPA)
Central HVAC integration (large facilities)	per project	Long duct runs; multi-zone distribution; BMS integration	DD-720, DD-960 (high static pressure)

Concealed Installation & Central Ventilation

The DD Series is built around three installation principles: an Ultra-Slim concealed housing for invisible integration into the building, single-inlet / single-outlet airflow for flexible duct routing, and standalone-or-integrated operation that lets the unit serve either as a dedicated dehumidification loop or as the moisture-control stage of a central ventilation system.

Ultra-Slim Concealed Housing. The cabinet is a low-profile rectangular form factor designed to fit within ceiling cavities, technical spaces, service risers, and mechanical rooms — invisible in the finished room with only intake and supply grilles visible. The galvanised-steel cabinet has a powder-coated finish and is rated for indoor installation as standard; with appropriate mounting, the larger models also tolerate sheltered outdoor installation.

Standalone or Central-Ventilation Integration. Each DD unit has one return-air intake and one supply-air outlet. In standalone mode, the unit pulls return air from the room, dehumidifies and filters it, and supplies it back — the simplest deployment for single-room or small-zone moisture control. In integrated mode, the supply outlet connects to a central ventilation system's distribution network: the DD unit becomes the moisture-control stage of the building's air handling, working in series with the main AHU or in parallel with rooftop / fresh-air equipment. Static pressure of 200 Pa (DD-168 to DD-480) or 400 Pa (DD-720, DD-960) is sufficient for long duct runs and multi-room distribution networks.

Duct Connections. Return and supply duct dimensions scale with unit size: 350×350 mm on DD-168 / DD-240; 750×450 mm return and 818×313 mm supply on DD-380 / DD-480; 1200×450 mm return and 1058×348 mm supply on DD-720 / DD-960. Drain connection (gravity) is provided on the cabinet's lower side. Maintenance access is through a removable inspection panel on the cabinet side — service can be performed in-place without dismounting.

How Does DD Compare?

The DD Series is not the only way to remove moisture from a commercial or industrial space. Each alternative is justified in specific conditions; this section gives the honest comparison.

Alternative	When it wins over DD	When DD wins
Portable / mobile dehumidifier (e.g. DanVex DEH-i)	Site work is occasional or temporary (post-flood restoration, drying after spillage, seasonal use, multi-site rotation). Capital cost lower; no installation labour.	Permanent installation, daily continuous operation, ducted distribution to multiple rooms, larger volumes, building aesthetic requirements (invisible equipment).
Wall- or floor-mounted dehumidifier (DanVex DEH-WP Series)	Single-room installation without ducting; no ceiling space available for concealed unit; capital-cost-sensitive projects on smaller volumes.	Multi-room distribution from one unit; aesthetic requirements (invisible installation); high capacities above 140 L/day; integration with existing ventilation network.
Central HVAC with humidity control (AHU with reheat coil or refrigerant-DX dehum stage)	New-build with humidity control specified at the AHU level; coordinated commissioning with the rest of the HVAC; very large multi-floor facilities.	Retrofit of existing buildings where the AHU cannot deliver target RH; dedicated humidity-control duty without changing the existing AHU; faster project timeline; lower capital cost than AHU modification.
Adsorption (desiccant) dehumidifier (DanVex AD Series)	Target RH below 35% at room temperature; cold-environment dehumidification (below +5 °C, where condensing dehumidifiers lose efficiency); industrial drying applications with very low dew-point targets.	Standard commercial and industrial RH targets (40–65%) at typical room temperatures (+15 to +30 °C); lower capital and running cost; simpler maintenance.

Key Technologies — at a Glance

Full Inverter technology across the range — inverter compressor and inverter-driven fan work as a pair; the compressor varies output continuously to match real moisture load, eliminating humidity swings and reducing power consumption versus fixed-speed dehumidifiers
Inverter-driven fan + electronic expansion valve (EEV) — the inverter-driven fan holds airflow steady against changing duct resistance with precise speed regulation, while the EEV meters refrigerant flow precisely across the full load range, keeping the refrigeration circuit at peak efficiency and capacity under varying conditions
E-Coating across the range — electrochemical anti-corrosion layer applied by immersion, depositing uniformly over the entire fin surface for 360° protection; resists moisture, mild acids and alkalis, salt vapours, and chlorinated air, suiting the full span of commercial and industrial environments from warehouses to pool halls and food production
Hot Gas Defrost — 3-minute defrost cycle versus 30 minutes for natural defrost; maintains operation from +5 °C without significant capacity loss
Ultra-Slim concealed housing — low-profile cabinet for installation within ceiling cavities and technical spaces; durable galvanised steel with powder-coated finish for indoor or sheltered outdoor placement
5-in-1 air quality sensor — CO₂, PM2.5, TVOC, relative humidity, and temperature monitored continuously on the return airstream; the unit adjusts operation based on indoor air quality, not only on a humidity setpoint
UV sterilisation lamp + Anion Generator — standard across the range; reduces airborne bacteria, mould spores, and pathogens without chemical dosing
Antifungus internal treatment — cabinet interior is treated with antimicrobial coating to suppress mould and bacterial growth in moist internal surfaces, supporting hygiene-sensitive applications
G4 + F7 filtration — two-stage particulate filtration (coarse + fine) on the return airstream; F7 captures fine dust and allergens. HEPA filtration is not standard on the DD Series — for HEPA H13 requirements see the DD-F Series or downstream filtration
Wi-Fi + Modbus RTU RS-485 — both protocols active simultaneously on every model; remote app control alongside BMS / SCADA integration via the wired bus. Auto-restart preserves all settings after power interruption

Full Specifications — DD Series

Parameter	DD-168	DD-240	DD-380	DD-480	DD-720	DD-960
Dehumidification capacity (30 °C / 80% RH)	140–210 L/day	220–260 L/day	300–420 L/day	480 L/day	720 L/day	960 L/day
Supply airflow	1700–2200 m³/h	1900–2700 m³/h	3500–3850 m³/h	4800–5300 m³/h	7500–9000 m³/h	9000–11 000 m³/h
External static pressure	200 Pa	200 Pa	200 Pa	200 Pa	400 Pa	400 Pa
Working humidity range	45–100% RH
Operating temperature range	+5 … +38 °C
Voltage / Frequency	380–415 V 3-phase / 50–60 Hz
Inverter system	Full Inverter
Heat exchanger protection	E-Coating
Defrost system	Hot Gas Defrost, 3 min cycle
Filtration	G4 + F7
Air purification	UV Steriliser + Anion Generator
Antifungus internal treatment	Yes
Air quality sensor	5-in-1: CO₂ · PM2.5 · TVOC · RH · T°
Connectivity	Wi-Fi + Modbus RTU RS-485
Rated power	1830–2520 W	3040–4200 W	4580–6246 W	9000 W	15 000 W	21 000 W
Current	2.7–3.8 A	4.6–6.4 A	6.9–11.6 A	16 A	26 A	37 A
Refrigerant	R-32 × 1600 g	R-32 × 1800 g	R-32 × 2500 g	R-32 × 2800 g	R-32 × 5400 g	R-32 × 7200 g
Noise level at 1 m	< 45 dB(A)	< 48 dB(A)	< 50 dB(A)	< 55 dB(A)	< 55 dB(A)	< 55 dB(A)
Return air duct	350×350 mm	350×350 mm	750×450 mm	750×450 mm	1200×450 mm	1200×450 mm
Supply air duct	350×350 mm	350×350 mm	818×313 mm	818×313 mm	1058×348 mm	1058×348 mm
Dimensions (L×W×H), mm	1250×820×600	1250×820×600	1370×1120×720	1370×1120×720	1700×1642×720	1700×1642×720
Net weight	108 kg	119 kg	189 kg	200 kg	422 kg	450 kg

FAQ — Frequently Asked Questions

How do I calculate the moisture load for a commercial or industrial space?

Moisture-load calculation (latent load) follows the same framework as cooling-load calculation in commercial HVAC. The total latent load is the sum of internal sources — people (typically 40–70 g/h per person at moderate activity), process moisture (cooking, laundry, swimming-pool evaporation, plant transpiration, drying operations), and infiltration of humid outdoor air; boundary sources — water-vapour migration through walls, vapour-permeable surfaces, and damp building materials drying out; operational sources — moisture released by cleaning cycles, condensation on cold surfaces (cold-room loading docks), and intermittent occupancy peaks. For typical commercial applications, ASHRAE provides moisture-emission rates by occupancy type, process type, and infiltration model. Indoor pool halls require specific calculation per ASHRAE TC 9.6 or the SwimAir method, factoring water surface area, water temperature, room air temperature, and activity factor (still water vs disturbed). For project-specific sizing, contact DanVex with project parameters — the dealer network can connect you with engineering support for moisture-load assessment.

What is Full Inverter technology, and why does it matter for industrial dehumidification?

Full Inverter is an inverter system: inverter compressor and inverter-driven fan work as a pair. The compressor varies its rotational speed continuously to match the real moisture load, instead of running at a fixed speed and cycling on/off like a conventional compressor. Three practical consequences: (1) Stable humidity — fixed-speed units overshoot and undershoot the setpoint as they cycle, producing humidity swings of ±10–15% RH; inverter units hold ±2–3% RH. This matters for museums, pharmaceutical production, plant cultivation, and any application with tight RH tolerance. (2) Energy efficiency — at part-load (which is the normal operating point most of the time), an inverter compressor draws less power than a fixed-speed unit running at full power and cycling; typical savings are 20–40% over a year. (3) Compressor longevity — fewer start-stop cycles means less mechanical stress and longer service life. Across the DD Series, Full Inverter is complemented by an electronic expansion valve (EEV), so airflow and refrigerant flow are both regulated continuously to hold capacity and efficiency steady under changing load.

What is E-Coating, and why does DanVex use it across the range?

E-Coating (electrochemical deposition coating) is an anti-corrosion treatment for the aluminium fins of a refrigerant heat exchanger. The coating is applied by immersing the heat exchanger in an electrically charged bath, so the polymer layer deposits uniformly across the entire fin surface — including internal and shaded areas that spray or dip coatings miss — giving full 360° protection. E-Coating resists moisture, mild acids and alkalis, salt vapours, and chlorinated air, which makes it suitable for the full span of environments the DD Series serves: warehouses, food production, manufacturing, museums, plant cultivation, and indoor pool halls. DanVex fits E-Coating on every model in the DD Series; standardising on a single, proven heat-exchanger protection simplifies specification and ensures consistent corrosion resistance regardless of which capacity you choose. The right model is selected by moisture load, airflow, and static pressure — not by coating type.

What static pressure does my ducting network require?

External static pressure (ESP) is the resistance the unit's fan must overcome in the duct network — the sum of duct friction (proportional to length and air velocity), fittings (elbows, transitions, dampers), filter pressure drop (which rises with filter loading), grilles and diffusers, and any silencers. Industry typical values: short residential and small-commercial duct loops 80–150 Pa; standard commercial duct networks 150–250 Pa; extended industrial or multi-zone networks 250–400 Pa. To size correctly, an HVAC engineer calculates total pressure drop from the project's specific duct geometry and adds a 20% safety margin to allow for filter loading over time. The DanVex DD Series provides two pressure tiers: 200 Pa on DD-168 / DD-240 / DD-380 / DD-480 (commercial and standard industrial duty); 400 Pa on DD-720 / DD-960 (industrial-scale and central-HVAC integration with extended duct networks). Select a unit with at least 20% headroom above the calculated value to ensure adequate airflow throughout the equipment's service life.

What humidity level should I maintain in common industrial applications?

Industry-standard targets vary by application: indoor pool halls 50–60% RH at +28 to +30 °C water and +30 °C air (chlorine off-gassing rises sharply above 60%); food production 45–65% by product class — drier for cured goods and chocolate (30–50%), higher for proofing rooms (70–85%); plant cultivation 60–70% in vegetative phase, 40–55% in flowering phase (to prevent bud rot); warehouses and logistics 50–65% for general goods, 30–45% for electronics and metal goods storage; museums and archives 45–55% with ±5% stability per ISO 11799 and IIC standards; pharmaceutical and clean production 30–50% per GMP requirements, with tight tolerance; manufacturing 40–60% for general work areas, lower for specific processes (composite curing, electronics assembly). Industrial sizing depends on the moisture load — process emission rate, infiltration, occupancy — not on floor area alone. For project-specific guidance, DanVex's dealer network can connect you with engineering support for moisture-load assessment.

What is Hot Gas Defrost, and how is it different from natural defrost?

When a dehumidifier operates near +5 to +10 °C, the evaporator coil temperature drops below 0 °C and condensate freezes onto the fins as ice. The unit then runs a defrost cycle. Natural defrost simply switches the compressor off and lets the fan circulate room air across the iced coil until the ice melts; this takes 20–30 minutes and during the cycle the unit produces no useful dehumidification. Hot Gas Defrost routes the compressor's hot discharge gas directly to the evaporator coil through a bypass valve. The ice melts in approximately 3 minutes, after which normal operation resumes. The practical effect is a 10× shorter defrost interruption — critical for continuous-duty industrial applications where humidity must remain stable around the clock. Hot Gas Defrost also extends the operating temperature range: condensing dehumidifiers with natural defrost lose useful capacity below about +12 °C; Hot Gas Defrost extends practical operation down to +5 °C without significant capacity loss. All DanVex DD models include Hot Gas Defrost as standard, as do DD-F and DD-FX.

Can a dehumidifier replace humidity control on an HVAC AHU, or do they work together?

Both approaches are used in commercial and industrial HVAC, and the right choice depends on the project. Integrated AHU humidity control uses a reheat coil or a refrigerant-DX dehumidification stage built into the air-handling unit; the AHU delivers conditioned air with controlled temperature and humidity in one pass. This works well in new-build projects where the AHU is sized and specified for the humidity duty from the start, and where the total HVAC load justifies the additional equipment cost. Dedicated dehumidifier in series or parallel with the AHU uses a separate dehumidification stage — like the DanVex DD Series — installed in the duct network downstream or upstream of the AHU, or in parallel on a dedicated humidity-control loop. This is the typical choice for retrofits where the existing AHU cannot deliver target RH, or where humidity duty is a localised requirement (one zone, one application) rather than a building-wide specification. Standalone dehumidifiers have lower capital cost than AHU modification, faster project timeline, and easier maintenance. In many large facilities, both approaches coexist — the AHU handles broad humidity within ±10%, and dedicated dehumidifiers in critical zones hold tighter tolerances.

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